i’m 15, 5 5, 135 pounds, 20% body fat. i wanna get down to 125 pounds & 17% body fat, is that bad?

websites are telling me im underweight. which makes no sense, cause i’m fairly stocky and athletically built, i’ve also got fat around my belly. & i really wanna get down to 125 and around 17 % body fat.
i eat 1200 calories a day, and i’d say i’m VERY healthy for my age. i have a cheat day which i allow myself to get a cafeteria cookie from school, or eat some popcorn (not too much) but not chips, or fast food ever. I play fairly high level softball and basketball (rep/travel) i also horseback ride a lot. i’ve been doing this for about a year, i used to be 150, then i got down to 135 in about a month and a half, but it seems like my body just doesn’t want to lose anymore. about a month ago i started to jog or go on the elliptical for 30 minutes (5 km) everyday, or on the bike for 45 minutes. why am i not losing weight? or is it more fat burning that i should be doing? what are some pointers?

Because the website calculators are based on Adults over 25 with seditary habits (little movement). NOT 15 yr olds that are still growing!

17% body fat for your age is a perfectly acceptable target. I wouldnt drop too much lower unless your an athlete, with a trainer to help monitor you.

Your exersize program sounds great. Just lay off processed foods – especially foods and drinks with sugar. Popcorn is empty calories. It has no benefit other then making you full. An apple and a big glass of water will do that and more.